field manual Telephone switchboard operating procedure field manual Telephone switchboard operating procedure manual Electrical instruments and telephones of the U.S. signal corps : revised 1910 Telephon- und Signalvorschrift für die k.u.k. Infanterie und die Jägertruppe Handbuch für den Telephon- und Signaldienst / J. Czermak training manual / united states army Telephone switchboard operator : students manual for all arms Telephone switchbord, type BD-14
